1. Field of the Invention
The present invention relates to manifold flanges for mounting on a cylinder head of internal combustion engines, comprising a manifold housing, a pipe connecting flange, and, for each cylinder, an individual flange with fastening means.
2. Description of the Background Art
Manifold flanges for attaching to the cylinder head of internal combustion engines include a manifold housing, which directs hot exhaust gases emerging from the cylinders to a pipe connecting flange where additional exhaust gas treatment elements are fastened. The fastening of the manifold flange to the cylinder head takes place with the aid of flanges, which are installed with the aid of stud bolts and nuts, or with the aid of screws. A seal is located between the cylinder head and the flange.
The manifold housing is heated to temperatures up to approximately 900° C. by the hot exhaust gases, causing it to expand accordingly. In contrast, the cylinder attachment flanges reach maximum temperatures of approximately 120° C., since over large areas they are in contact with the cylinder head, which is water cooled. The extreme temperature differences result in corresponding differences in expansion which must be compensated. The manifold housing accommodates some of the difference in expansion. The other part of the difference in expansion is compensated by sliding of the cylinder head attachment flange on the seal.
It is a matter of course that the compensation of expansion is optimal when the cylinder head attachment flanges are designed as individual flanges. However, manufacture and installation of manifold flanges with individual flanges is very cumbersome. Each individual flange must be handled individually. Each individual flange must be placed in an installation fixture for installation on the manifold pipes, in which process it is necessary to ensure by suitable means that no interchanging occurs during placement of the three, four, five, etc. individual flanges, which would make the manifold flange defective. This is unsatisfactory.